The present invention relates to hand grips, in particular, to hand grips that are utilized on handle bars or rudders of vehicles such as snow plows, ice boats, bicycles, motorcycles, ski mobiles and the like.
In particular, the invention relates to a heated hand grip of the above class, useful when such vehicles are operated in exposed winter atmospheres in which cold ambient temperatures are made more uncomfortable by wind chill developed as the vehicles progress at high speeds.
Representative examples of prior art heated hand grips are disclosed and described in U.S. Pat. Nos. 744,739, issued Nov. 24, 1903, by Fliess; and 1,830,221, issued Nov. 3, 1931, by Blue.
A particular prior art electrically heated hand grip, over which the present is an improvement, is disclosed and described in my prior U.S. Pat. No. 4,471,209, issued to me on Sept. 11, 1984, entitled ELECTRICALLY HEATED HAND GRIPS FOR VEHICLE HANDLE BARS.
In the '209 reference, which has enjoyed commercial success, there are several manufacturing and quality problems, which the present invention overcomes. For example, in the '209 device the heating wires are wound initially as a loose, fragile coil; thereafter the coil is placed on a metal mold core. The core is then inserted into a mating mold cavity and the internal sleeve 6, disclosed in FIGS. 2 and 4 of the '209 patent, is molded with the fragile coil of heating wire 10 being a mold insert.
In this procedure, there is danger of electrically short circuiting because the individual coils may be misplaced prior to mold closure.
To overcome this problem, the heating wire of the '209 disclosure was coated, prior to insertion into the mold, with high temperature insulating enamel.
After molding the internal sleeve, it was then necessary to remove the insulation at the terminal ends of the insulating wires to ensure good, reliable electrical conductivity when the wire ends were spliced to leads supplying electrical energy to the coil.
The structure and method of manufacture of the heated hand grips of the '209 reference had a further disadvantage and limitation. If one wished to change wire gauge or wire size, it was necessary to retool the male or female portions of the mold to accommodate new wire dimensions.
In addition, the manual steps required in winding the coils of heating wire and placing the winding about the mold core is tedious and highly labor intensive.
In like manner, the steps of exposing the terminal ends of the heating wire and removing the enamel insulation was highly labor intensive and time consuming.